Nanomagnet logic: progress toward system-level integration

Quoting the International Technology Roadmap for Semiconductors (ITRS) 2009 Emerging Research Devices section, 'Nanomagnetic logic (NML) has potential advantages relative to CMOS of being non-volatile, dense, low-power, and radiation-hard. Such magnetic elements are compatible with MRAM technology, which can provide input–output interfaces. Compatibility with MRAM also promises a natural integration of memory and logic. Nanomagnetic logic also appears to be scalable to the ultimate limit of using individual atomic spins.' This article reviews progress toward complete and reliable NML systems. More specifically, we (i) review experimental progress toward fundamental characteristics a device must possess if it is to be used in a digital system, (ii) consider how the NML design space may impact the system-level energy (especially when considering the clock needed to drive a computation), (iii) explain--using both the NML design space and a discussion of clocking as context—how reliable circuit operation may be achieved, (iv) highlight experimental efforts regarding CMOS friendly clock structures for NML systems, (v) explain how electrical I/O could be achieved, and (vi) conclude with a brief discussion of suitable architectures for this technology. Throughout the article, we attempt to identify important areas for future work.

Troglitazone induced apoptosis via PPARγ activated POX-induced ROS formation in HT29 cells

OBJECTIVE

In order to investigate the potential mechanisms in troglitazone-induced apoptosis in HT29 cells, the effects of PPARγ and POX-induced ROS were explored.

METHODS

[3- (4, 5)-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTT) assay, Annexin V and PI staining using FACS, plasmid transfection, ROS formation detected by DCFH staining, RNA interference, RT-PCR & RT-QPCR, and Western blotting analyses were employed to investigate the apoptotic effect of troglitazone and the potential role of PPARγ pathway and POX-induced ROS formation in HT29 cells.

RESULTS

Troglitazone was found to inhibit the growth of HT29 cells by induction of apoptosis. During this process, mitochondria related pathways including ROS formation, POX expression and cytochrome c release increased, which were inhibited by pretreatment with GW9662, a specific antagonist of PPARγ. These results illustrated that POX upregulation and ROS formation in apoptosis induced by troglitazone was modulated in PPARγ-dependent pattern. Furthermore, the inhibition of ROS and apoptosis after POX siRNA used in troglitazone-treated HT29 cells indicated that POX be essential in the ROS formation and PPARγ-dependent apoptosis induced by troglitazone.

CONCLUSION

The findings from this study showed that troglitazone-induced apoptosis was mediated by POX-induced ROS formation, at least partly, via PPARγ activation.

Small-incision orbicularis-levator fixation technique: a modified double-eyelid blepharoplasty for treating trichiasis in young Asian patients

Upper-eyelid trichiasis often occurs with a single puffy eyelid or shallow eyelid crease in young Asian patients. This study presents a novel modified trichiasis correction method to simultaneously treat trichiasis and create a natural eyelid crease. It combines the modified small-incision debulking procedure and the orbicularis-levator fixation technique. The eyelash lift angle (LA), body curl angle (BCA) and end curl angle (ECA) were quantitatively analysed. A total of 90 patients (152 trichiasis eyelids) were followed up for approximately 22 months. The LA changed from 24.32° ± 9.21°-54.12° ± 10.32° in the nasal section of the eyelid (section 1), from 21.03° ± 11.34°-52.03° ± 10.56° in the middle section of the eyelid (section 2) and from 23.31° ± 8.12°-63.15° ± 8.43° in the temporal section of the eyelid (section 3). All patients were satisfied with the eyelid-fold appearance. In conclusion, for young Asian patients with upper-eyelid trichiasis, the small-incision orbicularis-levator fixation technique is able to acquire a stable up-curved position of the eyelashes and satisfactory aesthetic results.

Non-majority magnetic logic gates: a review of experiments and future prospects for 'shape-based' logic

We discuss the experimental demonstration of non-majority, two-input, nanomagnet logic (NML) AND and OR gates. While gate designs still can incorporate the symmetric, rounded-rectangle magnets used in the three-input majority gate experiments by Imre (2006 Science 311 205-8), our new designs also leverage magnets with an edge that has a well-defined 'slant'. In rectangular and ellipsoid nanomagnets, the easy axis of the device coincides with its longer edge. For a magnet with a slanted edge, the easy and hard axes are 'tilted', and magnetic fields applied along the (geometrical) hard axis alone can set the easy axis magnetization state. This switching phenomenon can be employed to realize NML Boolean logic gates with both reduced footprints and critical path delays. Experimental demonstrations of two-input AND and OR gates are supported by corresponding micromagnetic simulations with temperature effects associated with a 300 K environment. Simulations suggest that the time evolution of experimentally demonstrated structures is correct, and that designs can also tolerate clock field misalignment. Additionally, simulations suggest that a slanted-edge 'compute magnet' can (i) be driven by two anti-ferromagnetically ordered lines of NML devices (for input) and (ii) drive an anti-ferromagnetically ordered line (for output). Both are essential if slanted-edge devices are to be used in NML circuits. We conclude with a discussion of extensibility and scaling prospects for shape-based computation with nanomagnets.

Biological properties of different protein extracts from selenium-enrichedGanoderma lucidum

Our previous studies showed that Ganoderma lucidum bio-transformed 20-30% of inorganic selenium from substrate to organic forms by preferentially incorporating selenium into proteins. In the present study, four kinds of protein extracts from selenium-enriched G. lucidum were prepared with different extracting solvents, which contain water-soluble, alkaline-soluble, salt-soluble and alcohol-soluble protein extracts, and the effects on antioxidant activity of characterizations of protein extracts were studied. Results showed that water-soluble extract showed strongest antioxidant properties among all extracts as suggested by spin trapping experiment due to its characterizations, followed by the alkaline-soluble > the salt-soluble > the alcohol-soluble protein extracts, a result demonstrating that selenium content and amino acids composition of the protein extracts play important and direct roles in enhancing their antioxidant activities, and the protein distribution and sugar content have an indirect effect by influencing the characters and structures. The activity of water-soluble crude protein was verified by CuSO4 Phen-Vc-H2O2-DNA chemiluminescent analysis, and it should be selected as the subject to be studied and purified further.

[Analysis of the extraction of red pellicle of walnut (Juglans regia L.) by ultraviolet-visible spectra and HPLC-ESI-MS(n)]

The extraction of the red pellicle of walnut (Juglans regia L.) was analyzed by UV-visible spectra and HPLC-ESI-MS(n) (high-performance-liquid-chromatography coupled with electrospray ionization mass spectrometry). The extraction in ethanol-HCl showed two absorption peaks at 560 and 591 nm respectively in the UV-Vis spectrum; after purified by lead acetate and thin-layer-chromatography, the extraction in ethanol-HCl showed 4 absorption peaks at 340, 370, 552 and 585 nm respectively. These results testified that the anthocyanin was in the extraction. Six molecular ion peaks (m/z) occurred on MS: 301, 481, 633, 783, 785 and 950, which was identified as ellagic acid, Hexahydroxydiphenoyl(HHDP)-glucose, Galloyl-HHDP-glucose, Di-HHDP-glucose, Di-Galloyl-HHDP-glucose, and HHDP-Valoneoyl-glucose respectively.

[Effects of high pulsed electric field on the secondary and tertiary structure of lipoxygenase]

The effect of pulsed electric field (PEF) on the secondary and tertiary structure of lipoxygenase (LOX) in a buffer solution was analyzed using far UV-circular dichroism (CD) and fluorescence spectrophotometry, respectively. The secondary and tertiary structure of LOX changed after PEF treatment. The CD spectra of LOX also changed, with the intensity of two negative peaks and the content of alpha-helix significantly decreased (p < 0.05). The decrease in alpha-helix content in LOX showed a good linear correlation with the electric field strength. The fluorescence intensity of LOX increased, and the relative fluorescence intensity of the two characteristic peaks of LOX emission spectra at 337 nm and 583 nm also showed a good linear correlation with the electric field strength. These results showed that the activity inactivation of LOX may be due to the alteration in secondary structure, and both had a good relation.

[Determination of mineral elements in eight pear varieties by ICP-MS after microwave-assisted digestion]

A study was carried out on the contents of mineral elements such as Na, K, Ca, Mg, Zn, Cu, Fe, Mn and B in eight different pear varieties by ICP-MS after microwave-assisted digestion. The results indicated that the main elements of the eight pears are similar, but the content of each element is different. The content of K is the highest in the detected pears, followed by Mg, Ca and Na. Compared with the reference value of AIJN (Association of Industry of Juices and Nectars from fruits and vegetables of the European Union), the range scale of K, Mg, and Ca was higher than that of the AIJN, while the content of Na element was lower than that of the AIJN, and other elements content was consistent with it.

[The characteristic analysis of several mineral contents in Chinese orange juice]

A study was carried out on the contents of mineral elements such as K, Ca, Na, and Mg in seven different orange varieties, namely Pineapple orange, Hamlin, Trovita, Jincheng, 1,232 Tangor, Olinda Valencia and Delta Valencia, by flame atomic absorption spectrometry. The results indicated that the content sequence of different nutritional elements was K > Mg > Ca > Na, with a range of 1,233.75-1,866.23, 77.51-167.15, 49.32-125.29 and 1.22-9.26 mg x L(-1) respectively. The range scale of the four elements was largely consistent with the reference value of AIJN (Association of the Industry of Juices and Nectars from Fruits and Vegetables of the European Union). The samples can be clustered into 2 groups by factor analysis, and lower Na content would be the characteristic of the Valencia varieties. All these data would offer important information for orange juice adulteration determination and quality evaluation.

Resveratrol reduces endothelial progenitor cells senescence through augmentation of telomerase activity by Akt-dependent mechanisms

BACKGROUND AND PURPOSE

Recent studies have shown that resveratrol increased endothelial progenitor cells (EPCs) numbers and functional activity. However, the mechanisms remain to be determined. Previous studies have demonstrated that increased EPC numbers and activity were associated with the inhibition of EPC senescence, which involves activation of telomerase. Therefore, we investigated whether resveratrol inhibits the onset of EPC senescence through telomerase activation, leading to potentiation of cellular activity.

EXPERIMENTAL APPROACH

After prolonged in vitro cultivation, EPCs were incubated with or without resveratrol. The senescence of EPCs were determined by acidic beta-galactosidase staining. The bromo-deoxyuridine incorporation assay or a modified Boyden chamber assay were employed to assess proliferative or migratory capacity, respectively. To further examine the underlying mechanisms of these effects, we measured telomerase activity and the phosphorylation of Akt by western blotting.

KEY RESULTS

Resveratrol dose dependently prevented the onset of EPCs senescence and increased the proliferation and migration of EPCs. The effect of resveratrol on senescence could not be abolished by eNOS inhibitor or by an oestrogenic receptor antagonist. Resveratrol significantly increased telomerase activity and Akt phosphorylation. Pre-treatment with the PI3K inhibitor, LY294002, significantly attenuated resveratrol-induced telomerase activity.

CONCLUSIONS AND IMPLICATIONS

Resveratrol delayed the onset of EPC senescence and this effect was accompanied by activation of telomerase through the PI3K-Akt signalling pathway. The inhibition of EPCs senescence by resveratrol might protect EPCs against dysfunction induced by pathological factors in vivo and improve EPC functional activities in a way that may be important for cell therapy.

Mechanisms involved in ceramide-induced cell cycle arrest in human hepatocarcinoma cells

AIM: To investigate the effect of ceramide on the cell cycle in human hepatocarcinoma Bel7402 cells. Possible molecular mechanisms were explored.

METHODS: [3- (4, 5)-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTT) assay, plasmid transfection, reporter assay, FACS and Western blotting analyses were employed to investigate the effect and the related molecular mechanisms of C2-ceramide on the cell cycle of Bel7402 cells.

RESULTS: C2-ceramide was found to inhibit the growth of Bel7402 cells by inducing cell cycle arrest. During the process, the expression of p21 protein increased, while that of cyclinD1, phospho-ERK1/2 and c-myc decreased. Furthermore, the level of CDK7 was downregulated, while the transcriptional activity of PPARγ was upregulated. Addition of GW9662, which is a PPARγ specific antagonist, could reserve the modulation action on CDK7.

CONCLUSION: Our results support the hypothesis that cell cycle arrest induced by C2-ceramide may be mediated via accumulation of p21 and reduction of cyclinD1 and CDK7, at least partly, through PPARγ activation. The ERK signaling pathway was involved in this process.

[Expression of Nestin following focal cerebral ischemia-reperfusion in rats]

OBJECTIVE

To study the expession of Nestin after focal ischemia-reperfusion in rats.

METHODS

The model of acute reperfusion injury after cerebral ischemia in rat was made by middle cerebral artery occlusion. All animals were allowed 2 h ischemia and sacrificed after different durations of reperfusion (6 h, 12 h, 24 h, 72 h, 7 d, 14 d). The expression of Nestin was detected with an immunohistochemical approach.

RESULTS

The number of Nestin- immunoreactive cells at 6 h after reperfusion in the ischemic side started to increase markedly and showed significant difference, compared with the Sham group (P < 0.05). The expression of Nestin and the number of Nestin positive cells with Brdu labeled peaked at 7 d after reperfusion and then were down-regulated at 14 d.

CONCLUSION

The study implies cerebral ischemia could upregulate the expression of Nestin and induce the proliferation of nervous stem cells.

[Isolation and identification Alicyclobacillus from concentrated apple juice processing]

The forty-five strains of bacteria have been isolated from concentrated apple juice. All of them can grow at K agar (pH 4.0), but can't grow at LB palate (pH 7.0). By using heat resistance test, 38 strains of these bacteria could be classified into 3 groups according to their spore-forming time. 33 strains of them had the same spore-forming time as DSM 3922, which could produce spores within 48 h when cultivated at 45 degrees C; 3 strains of them could grow very fast and produced spores within 17 h; and 3 strains of them produced spores 48h later. Based on the results of 16S rDNA PCR-RFLP analysis, 7 strains of unknown, probably new species and 5 reference strains were selected for 19 phenotypic characteristics test and the result were analyses by UPGMA. The results of phenotypic characteristics test had good agreement with 16S rDNA PCR-RFLP analyses, that the 7 strains were different from all the 5 reference strains, they are new species of Alicyclobacillus.

Effect of Zn(II) on the structure and biological activity of natural beta-NGF

Only beta-NGF, the subunit of the 7S NGF complex, exhibits NGF activity, but the function of the zinc ion in native beta-NGF has received little attention. Flameless atomic absorption spectroscopy (FAAS) measurements reveal that native beta-NGF contains Zn(II) with a Zn(II)/beta-NGF stoichiometry of 1:14.6. The presence of Zn(II) in the native molecule results in significant changes of the secondary structure and local tertiary structure around Trp(s) with respect to those of apo beta-NGF, as suggested by spectra of fluorescence and circular dichrosim. Stopped-flow studies show that there are at least two steps during the interaction of Zn(II) with the apo form. In comparison with its apo form, the native beta-NGF shows a higher ability to trigger the proliferation of TF1 cells and mediate the survival of PC12. Thus it is most likely that the structural changes caused by the presence of Zn(II) directly lead to the increase in the biological activity of beta-NGF. All results indicate that Zn(II) in native beta-NGF plays an important role in the structure and the biological activity of the protein.

[Analysis of Leishmania species and strains from China by RAPD technique]

OBJECTIVE

To analyze genetic relationship of Leishmania species and strains from China by RAPD technique.

METHODS

DNAs from Leishmania strains, including L. donovani (L. d.) isolates from patients, dogs and sandflies of three different foci in China and international reference strains, were amplified by seven random primers. The DNA polymorphic bands detected were analyzed by clustering analysis with SPSS software.

RESULTS

1. L. d. isolates from hill and plain foci in China were divided into two groups. The genetic distance of L. d. isolates is distant between them. 2. L. d. XJ771, L. d. XJ901, L. d. XJ801 from desert, vicinity of desert, and plain regions in Xinjiang were in the same group. It indicated that the genetic distance among L. d. isolates from the three regions is close. 3. L. d. isolated from VL patients and dogs in hill foci could not be discriminated distintly, showing high homology between them. 4. L. d. DD8 from India, the reference strain of plain type, was clustered with L. d. isolates from plain foci in China. It provided scientific basis for the viewpoint "Kala Azar from east area of China is similar to that from India". 5. L. infantum and L. d. isolates from hill foci in China were clustered into different groups. 6. The genetic distance is close between L. d. isolates from plain foci in China and L. d. Jed; 7. L. infantum and L. tropica showed the closest genetic distance.

CONCLUSION

Differences at genetic level exist in Leishmania isolates from different foci in China.

[Cloning and sequence analysis of SSU rRNA gene of cutaneous leishmaniasis pathogen from Xinjiang of China]

OBJECTIVE

By sequencing of SSU rRNA gene cloning from Xinjiang cutaneous leishmaniasis pathogen (XJCLP) to provide evidence for identification of the pathogen.

METHODS

By PCR assay with primers R222 and R333, the specific fragment had been produced from SSU rRNA gene of XJCLP, L. infantum, L. tropica and cloned into pGEM-T Easy vector. The clones were sequenced by the Sanger dideoxy-mediated chain termination method, analysis of SSU rRNA gene sequences from XJCLP, L. tropica, L. infantum with DNASIS.

RESULTS

Sequence analysis showed that the specific fragment of SSU rRNA gene from XJCLP, L. infantum, L. tropica, were all 394 bp in length. There were 391 bases identical and three point mutations between the sequences of XJCLP and L. tropica, the similarity being 99.2%; 390 bases identical and three point mutations and one insertion/deletion between the sequences of XJCLP and L. infantum, the similarity being 99.0%. One insertion/deletion between the sequences of L. tropica and L. infantum, the similarity being 99.7%. The primary and secondary structures of SSU rRNA gene from XJCLP differed from those of L. infantum and L. tropica. A retrieval from GenBank confirmed that these 394 bp sequence are new gene sequences.

CONCLUSION

The primary and secondary structures of SSU rRNA gene from XJCLP, L. infantum, L. tropica were different. 394 bp sequence from SSU rRNA gene of XJCLP is a new gene sequence.

[Sequence analysis of SSU rDNA variable regions of Leishmania isolates from hilly foci and plain foci of China]

OBJECTIVE

To analyze the sequence difference of the SSU rDNA variable regions of Leishmania isolates from hilly foci and plain foci of China.

METHODS

Specific SSU rDNA fragments from nuclear DNA of five Leishmania species and isolates were amplified by PCR. The amplified DNA fragments were cloned into pGEMR-T Easy vector. The specific fragments were sequenced by the automated DNA sequencer.

RESULTS

Sequence analysis showed that the amplified DNA fragments of five Leishmania species and isolates were all 392 bp in length, point mutations were located in the two unique sequence (UQ-I and UQ-II); L. d. SC10 and L. d. GS7 had two same point mutations in UQ-II, only L. d. GS7 had one in UQ-I; no insertion/deletion.

CONCLUSION

Sequence difference of the SSU rDNA variable region existed between Leishmania isolates from hilly foci and plain foci; The sequences of the SSU rDNA variable regions of L. d. SD2 isolate and L. infantum were identical.

[Sphingolipid and apoptosis]

Over the last decade, considerable progress has been made in the study of sphingolipids with the development of biological techniques. Sphingolipids play important roles in diverse physiological process, including cytoskeleton migration, angiogenesis, embryonic development and signal transduction. Except for this, the lastest evidence has suggested that sphingolipids and their metabolite (ceramide, sphingosine, sphingosine 1-phosphate) can induce apoptosis in a wide variety of tumor cell lines such as LoVo HT29, Bel7402, A549, CNE2 cells. This paper is attempted to review the recent advances of investigation into the relationship between sphingolipids and apoptosis.

Assessment of the ratio of pollen to seed flow in a cline for genetic variation in a quantitative trait

A dispersal-selection cline model is analysed to evaluate the role of the ratio of pollen to seed flow (r) in spatial genetic variation, with a focus on clines in additive and dominant variances of major genes affecting a quantitative trait, assuming one locus with two alleles, no genetic drift and no mutation. It is shown that under weak selection, steady-state departures from the value at Hardy-Weinberg equilibrium (HWE) for genotype frequency (D) and additive variance (DeltaVa) generally display a small value on one side of the selection boundary point, a high value around the point, and a moderate value on the other side of the boundary point. A large value of r can enhance formation of this pattern. However, this is not the case for clines in the average effect of a gene substitution (Deltaalpha) or in dominance variance (DeltaVd), where large values of r can eradicate the clines. Direct use of their values at HWE to approximate the real case is acceptable. There is an expected turning point that divides clines of either additive variance or dominance variance into two subclines, each with a shorter width than that of allele frequency. Integration of these properties can help to indicate the existence of major genes affecting a quantitative trait.